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Author Topic:   Prop assistance please
Want_a_Whaler posted 03-30-2003 01:03 PM ET (US)   Profile for Want_a_Whaler   Send Email to Want_a_Whaler  
Okay..I took my Outrage II 17' out for her extended maiden voyage. She has a 90hp 4 stroke Honda. The prop that came with it is to large. With a full tank of gas and 2-3 people I can only get 4100 RPM at WOT. I pulled the prop and it has not markings to tell me what I have. Does anyone have suggestions as to prop size and how can I measure the prop pitch on my own?
Also, there are a few gouges in the gelcoat that I would like to patch. Can anyone recommend a good patching product for deep scratches and gelcoat holes on the keel?
jimh posted 03-30-2003 07:55 PM ET (US)     Profile for jimh  Send Email to jimh     
Lacking any markings on the propeller, probably the only way to deduce its pitch would be to take it to a propeller shop. They typically have "pitch blocks" that can be fitted to discover the pitch.

My guess would be that it is at least a 19-inch pitch. You can use the propeller calculator to make a more educated guess, but you must provide the lower unit gear ratio.

Enter the RPM, gear ratio, and Speed. Estimate the slip at about 10-percent, and the calculator will compute the pitch.

It is a very handy device!


Information about your lower unit gear ratio will be found in your owner's manual. Also check there for the maximum rated crankcase speed (RPM).

And you might also find information on the propeller if it is the OEM propeller.

Jiles posted 03-30-2003 09:27 PM ET (US)     Profile for Jiles    
I don't know if this will help, but I had a propeller that dia/pitch was not readable but the part number was. I simply typed the part number on the internet home page and was given several web sites that have this number. It turned out to be a Mishigan wheel prop and I got all the information I needed. Just thought it might work for you.
Sal DiMercurio posted 03-30-2003 10:27 PM ET (US)     Profile for Sal DiMercurio  Send Email to Sal DiMercurio     
Jim, i'v got the feeling he's twisting a 25 or 27 pitch, as I think [ off the top of my head ] that engine redlines around 6,000 rpms.
If thats the case, he's 1,900 rpms off, like 10" of pitch.
I would think that engine should be able to swing a 17 pitch on that boat.
It's either "WAYYYYY" over or the engine is not running right.
I know of no faster way to ruin an engine then over proping one, other then no oil or the water going out.
Perry posted 03-30-2003 11:36 PM ET (US)     Profile for Perry  Send Email to Perry     
I have the same motor on my 16' Dauntless. Your boat is a foot longer and 200 lbs heaver but both have very similar Accutrack hulls. A 13 1/4" 15 pitch stainless steel prop should work fine. I use it on my boat and it turns 6200 rpm under light load. The prop caculator works but along with the gear ratio (2.3) and rpm, you'll need a speed to figure prop size. Where is the anti-cavitation plate in relation to the bottom of the hull at the transom? I gained 200 rpm by raising motor 2 holes (1.5") Is your current prop alluminum? Did you look inside the hub for any markings?
Want_a_Whaler posted 03-31-2003 02:43 PM ET (US)     Profile for Want_a_Whaler  Send Email to Want_a_Whaler     
Okay...I brought the prop to the prop shop today and found out it was a 17" pitch. The guy at the shop gave me a loaner 15" to try out. As for the cavitation plate..It is located about level with the bottom of the hull.
Bigshot posted 03-31-2003 02:56 PM ET (US)     Profile for Bigshot  Send Email to Bigshot     
How far up are you trimming the engine? Trim till she blows out and then trim it down till it grabs again, that will give you a good idea. If I trim mine in, it won't rev either, you must trim out. From what Perry says, a 15 should do you. If you can get 5500 plus she should do fine. what did it do on the test run, how big is the tank? A 70 gallon tank holds 500+ lbs of gas, enough to cripple a boat with your configuration. With a 90 4 stroke, I would not run that tank full unless you need to, too much weight.
Want_a_Whaler posted 03-31-2003 03:06 PM ET (US)     Profile for Want_a_Whaler  Send Email to Want_a_Whaler     
Thanks Bigshot. The boat has a 56 gallon tank and it is filled to the rim! I am sure that is a big part of the problem. The worst part is that we ran it for 6 hours and barely made the fuel gauge needle move!
If the 15" doesn't improve the performance adequately, I may manually drain the tank to about 1/2 full.
I hope to try the 15" by Wednesday.
Perry posted 03-31-2003 04:05 PM ET (US)     Profile for Perry  Send Email to Perry     
Bigshot brings up a good point. Trim motor all the way in at hole shot then trim out once on plane. If the 15 pitch prop doesn't get you to 5800 rpm, I would seriously consider raising your motor one or two holes. This will reduce drag alowing your motor to rev higher and perform better. Do you have a way to measure speed? A hand held gps costs a little over $100 and are very handy.
Want_a_Whaler posted 03-31-2003 04:55 PM ET (US)     Profile for Want_a_Whaler  Send Email to Want_a_Whaler     
Perry...I have a Hummingbird chart with a speedo on it. At 4100 RPM (WOT) with the 17" it read 27mph.
Sal DiMercurio posted 03-31-2003 08:21 PM ET (US)     Profile for Sal DiMercurio  Send Email to Sal DiMercurio     
If you can't run that boat with a full tank, what good is it ? your grossly under powered, either trimmed in or out.
Going from a 17 pitch to a 15 pitch & all the trimming in the world, certainly "WILL NOT" increase your rpms by 1,900
What is the minimum recommended hp for that boat?
4,100 rpms for a 6,000 rpm engine isn't even close to having enough horses.
You can raise the engine all you want, even 4 holes, add a 15 pitch prop, & 1,900 rpms will become 1,200 rpms below where it should run.
What is the maximum hp recommendation from Whaler ?
This is a classic case of making the mistake of not buying the maximum recommended hp for any boat.
What good is a boat if you can't fill the tank.
Believe me, if your only getting 4,100 rpms at wot, your not getting anything close to the fuel economy you think you are, & your really driving that engine to a quick death if you continue to operate it at below it's easy breathing mode.
Perry posted 03-31-2003 09:42 PM ET (US)     Profile for Perry  Send Email to Perry     
Don't get too discouraged if the motor doesn't perform to your liking on your hull. You got a great deal on the boat and you should be able to get a good price for the Honda if it doesn't work out. Do some more trials in the water and make a decision from there.
Sal DiMercurio posted 04-01-2003 12:21 AM ET (US)     Profile for Sal DiMercurio  Send Email to Sal DiMercurio     
Perry is right, the engine should sell pretty fast, but 4,100 rpms sure dosen't say much for a 90 hp 4 stroke.
Are you sure it's running right ?
Want_a_Whaler posted 04-01-2003 08:54 AM ET (US)     Profile for Want_a_Whaler  Send Email to Want_a_Whaler     
Am I sure its running right?
Well, it doesn't miss or hesitate, the compression is good, the lower unit oil seems to be in pretty good shape. I can rev the engine to redline easily when it is in neutral. The engine does not smoke. It runs at normal temperature. What else could cause poor top end performance?
I ran the 15" prop last night and got up to around 4600 RPM and 30-31 mph. Do you think it makes sense to pitch down again? What would be a next logical step? 13.5" pitch?
Thanks for any help
As for selling the engine and repowering, that is not an option for me right now. I bought this as a used combo and the price was right but I can't afford the difference right now.
Bigshot posted 04-01-2003 10:07 AM ET (US)     Profile for Bigshot  Send Email to Bigshot     
Calm down everyone!

Take it to a mechanic & stop reving it in neutral(unless you want to blow it up). Have it looked at and then go from there. Your tach may not work right either but I am thinking more like you are only getting 3.5 cyls. Maybe a carb is gummed, that boat has been sitting a while. Have it looked at, they can tell everything from hooking it to a laptop.

Bigshot posted 04-01-2003 10:08 AM ET (US)     Profile for Bigshot  Send Email to Bigshot     
PS I thought you sea trialed this? If not.....tsk tsk.
Want_a_Whaler posted 04-01-2003 11:31 AM ET (US)     Profile for Want_a_Whaler  Send Email to Want_a_Whaler     
I'm calm...I was honestly curious. I only posted the engine's current status so you guys could give me more feedback. I hope my post didn't seem like I was defensive...I am just trying to provide as much info as possible to anyone that has any ideas.
Thanks for your help everyone.
Bigshot posted 04-01-2003 11:33 AM ET (US)     Profile for Bigshot  Send Email to Bigshot     
Not that....just don't want you to think you made a bad decision or trade in your engine just because of a gummed up carb or a coil not working right, etc. Take it to a dealer and have it checked.
Perry posted 04-01-2003 12:08 PM ET (US)     Profile for Perry  Send Email to Perry     
4600 rpm with a 15 pitch prop does lead me to believe that a carb may be gummed up or a plug may not be firing. I ran my boat on sunday with the same prop. I had 6 adults (over 1000 lbs.) and I only lost one mph and 1000 rpm at wot. Your boat should have similar performance. Bigshot is right, take it to a mechanic and have it looked at.
Want_a_Whaler posted 04-01-2003 12:14 PM ET (US)     Profile for Want_a_Whaler  Send Email to Want_a_Whaler     
I will give the mechanic a try. Would'nt the engine run rough if a cylinder wasn't firing? Perhaps because I don't have a baseline to compare to the engine is running rough and I just don't realize it?
T Party posted 04-01-2003 01:50 PM ET (US)     Profile for T Party    
Because you don't have much experience with this motor, you might not know the difference. These motors can run on three cylinders - believe me - I had a problem for a while with a motor that seemed to sound OK, but would choke out in reverse and didn't want to idle. I could run it forward seemingly without much problem (it ran anyway, and not particularly rough), but the power was sapped. Bad coil. I probably ran it for five hours before I realized that it wasn't just the idle setting on the carbs, as the problem got worse.
Good luck.
Perry posted 04-01-2003 01:57 PM ET (US)     Profile for Perry  Send Email to Perry     
Oops, I meant that I lost 1 mph and 100 rpm at WOT with 6 adults.
Bigshot posted 04-01-2003 02:33 PM ET (US)     Profile for Bigshot  Send Email to Bigshot     

Check to see that your plug wires are not crossed. When you did a compression test you may have put #2 wire on #3, etc. It will still run but not right.

Bigshot posted 04-01-2003 02:34 PM ET (US)     Profile for Bigshot  Send Email to Bigshot     
PS also go back to the 17" prop. It was probably good before.
Want_a_Whaler posted 04-01-2003 02:44 PM ET (US)     Profile for Want_a_Whaler  Send Email to Want_a_Whaler     
Thanks Big...I went home at lunch and did a little more troubleshooting. The plug wires are clearly marked so that was not an issue. I ran the boat (with muffs) up to temp and put it at a fast idle (1000 RPM). I pulled each plug wire individually to check for spark and all had spark and all caused the engine to slow and miss slightly as they were pulled.
I don't know if this rules out a power pack issue or not but I feel better knowing all cylinders are firing. Perhaps its still a carb issue ?? My friend and mechanic will be over tonight to do some more troubleshooting but he has had limited 4 stroke experience.
newt posted 04-01-2003 03:24 PM ET (US)     Profile for newt  Send Email to newt     
I don't know that pulling each plug wire will rule out a problem. I had the same results on an older 6 cyl merc (meaning each time I removed a wire, I would lose some rpms). It turned out to have a bad stator.
Sal DiMercurio posted 04-01-2003 04:00 PM ET (US)     Profile for Sal DiMercurio  Send Email to Sal DiMercurio     
Isn't that engine fuel injected instead of carbbed ?
Strange the engine gained 500 rpms with 2" less pitch, it should have gained only 400,....200 rpms per inch of pitch removed.
I really don't feel changing prps is going to help much, as that engine should have spun the 15 pitch close to 6,000 rpms.
I have a hunch your sync & link [ linkage ]are out of adjustment & she's not getting full throttle.
It sounds like the tach is working fine as 4,100 rpms should push that boat right about the speed your not getting.
Have a tech check the sync & link, bet thats your problem.
Want_a_Whaler posted 04-01-2003 04:48 PM ET (US)     Profile for Want_a_Whaler  Send Email to Want_a_Whaler     
Sal...If the linkage was an issue would I still be able to rev the engine to full RPM in neutral? Does the linkage need to be adjusted for load? Thanks
Perry posted 04-01-2003 05:37 PM ET (US)     Profile for Perry  Send Email to Perry     
Sal has a good point. When I got my motor from the dealer, who installed it, the throttle linkage was not set to give the motor full throttle. Look on the right side of motor where the carbs are. You'll see the linkage and a plastic wheel that the throttle cable is attached to (right above dip stick). Advance the throttle all the way and see if the plastic rod extends all the way to the end of the gap in the track. If the rod stops in the middle you are not getting full throttle.
Sal DiMercurio posted 04-01-2003 05:37 PM ET (US)     Profile for Sal DiMercurio  Send Email to Sal DiMercurio     
First of all, you absolutly "NEVER" rev an outboard over 2,000 rpms in neutral.
They are built to operate under a load.
You wouldn't be able to tell if it was getting full throttle while in neutral anyhow, as it would be free turning without a load, so forget over reving her while in neutral.
I'm almost certain your linkage is not right as it seems the engine is running smooth , not missing or struggling to continue running.
If you were running at wot last weekend [ 4,100 rpms ] , your fuel would have gone down very quickly at only 4,100 rpms wide open throttle.
But since you say it has hardly moved, it makes me believe you really weren't poring the coals to her & your only getting about 3/4 throttle.
Have a tech check the linkage, hopefully i'm right cause it's a very inexpensive fix & not time consuming.
Let us know what he finds.
Want_a_Whaler posted 04-02-2003 09:04 AM ET (US)     Profile for Want_a_Whaler  Send Email to Want_a_Whaler     
Thanks guys for your continued assistance. Okay...I discovered the sliding linkage last night while checking the full throttle position. Mine also only advanced to the halfway point. I adjusted the cable so that the pin would slide all the way to the top. I ran the 15" and got the engine up to 48-4900 RPM. I gained 1-2 mph. Better, but I noticed something new. One time, as I was backing off from WOT, the engine acted like someone had briefly shot it with Nitrous because it briefly revved past 5100 RPM. And the boat had a noticeable lurch.
I am beginning to suspect either electronic or carb issues.
Some additional info. The boat was filled with gas over a year ago and had been in storage for some time before I purchased it. If the carbs were gummed up and/or the fuel was too old (high speed jets?) could this cause a power reduction without causing missing? On occassion the engine will hesitate if you try to accelerate with load.
Also, since I advanced the linkage, I notice that the engine misses slightly at WOT like one cylinder is not getting fuel or the spark had been briefly taken away. ??
Bigshot posted 04-02-2003 10:07 AM ET (US)     Profile for Bigshot  Send Email to Bigshot     
Man you are gonna blow that thing up if you keep messing with it. You have gas or spark issues but probably gas. Have you checked the gas filter(water seperator)? Did you mess with the timing instead of throttle linkage....hopefully not. Try running a seperate tank(6gal). Year old gas can be 70 octane and she won't run good on that.
Want_a_Whaler posted 04-02-2003 11:49 AM ET (US)     Profile for Want_a_Whaler  Send Email to Want_a_Whaler     
Please Big...Don't take this as anything but information, but suffice it to say that i have enough mechanical knowledge to avoid "blowing up" my engine.
I've owned several 2 stroke engines in the past and have done pretty major service (short of overhauls) on them myself. I always take a conservative approach when troubleshooting an engine problem.
If my prior posts mislead anyone to think that I am a newbie to engines or outboards I apologize. I am just dealing with issues that I have not had to deal with in boats I've owned previously and I want to provide any info I can to those who might be helpful.
BTW..I don't throttle my engine in neutral, it just happened during the sea trial with the seller. I explained to him that it was a bad idea.

I spoke with a local honda tech today and really got no new info other than "it could be a number of things". I understand that it would just be easier to drop it off to him and let him start the billing clock but I want to eliminate as many possibilities as I can and be fully educated on what the motor is doing (or not doing) before I have it serviced since the motor is new to me. The tech did say to go ahead and drop down to a smaller prop to see if I can get RPMs, so that will be my final test.
I have no experience with this local technician and I have heard or read about too many horror stories regarding marine mechanics to just drop it off blind.
I will go ahead and try a 13" pitch prop because I want to see if the engine misbehaves in its WOT operating range. If it looks like the engine is not under enough load and the prop is just slipping, I will not push it. This test , I believe, will be additional useful information for the shop when I bring it in.
Thanks again everyone for your comments/feedback.

Bigshot posted 04-02-2003 02:21 PM ET (US)     Profile for Bigshot  Send Email to Bigshot     
Then you should know that if you have a lean carb or timing that is wrong, you WILL do damage....more so on a 2 stroke. The neutral thing threw me off, especially since you mentioned it twice....sorry.

Try this and forget the 13" prop. Put the 17" back on and remove the air box in front of the carbs. Get a spraybottle and fill with gas. get the boat running WOT(while somebody is driving) and spray in each carb throat(1 at a time). If it bogs down, carb is OK. If it picks up, carb is lean. try running a tank of Techron or Berryman's B-12 through it after you test it. Take it easy on it while you run the 6 gal tank with premium and techron in it(use the whole jar). It should clean out the carbs. The old gas might be an issue as well. Before I did anything I would get a 6 gal tank and do as above with the spraybottle.

Let us know what gives.

Perry posted 04-02-2003 02:30 PM ET (US)     Profile for Perry  Send Email to Perry     
The 17 pitch prop is too big. I tried it on my boat which is smaller and lighter than yours and hole shot suffered big time. Removing the air filter is not an option because you cannot access the bolts without removing the manifold. Try the 13 pitch prop with some clean gas in a portible tank. You can spray carb cleaner into the opening in the air box to try to clean any possible gumming in the carbs. If this doesn't improve performance you may need to take it to a mechanic to check valve clearance, timing, carb sync etc. Good luck...
Bigshot posted 04-02-2003 03:05 PM ET (US)     Profile for Bigshot  Send Email to Bigshot     
Guess I should look at a Honda before I open my mouth.....was a great idea though.

If removing the carb cover is not possible then try spraying some gas into the intake and see if she picks up speed. It won't isolate what carb but may give you an idea you are running too lean etc. Try the techron in the 6 gallon tank though. Run it for about 1/2 hour on the muffs and shut it down and let it sit overnight. The techron in the carbs should loosen overnight and then hopefully running it through the next day will clean them up. if not.....take it to a dealer and let them run diagnostics. They can determine how each cyl is firing, etc and may be able to pinpoint it fairly quickly. Diagnostic time should not take more than $100 in labor. In FL if they go over $100 without telling you, you don't have to pay.

Bigshot posted 04-02-2003 03:07 PM ET (US)     Profile for Bigshot  Send Email to Bigshot     
PS I had a carb gum up on me in less than a month in FL heat......not hard to do. Hence why JB and I really stress the EFI's on newer engines being gas quality is SHONGO.
Sal DiMercurio posted 04-02-2003 05:38 PM ET (US)     Profile for Sal DiMercurio  Send Email to Sal DiMercurio     
Wow, I doubt if 1 year old gas in a 2 stroke wont even fire, but I don't know about a 4 stroke.
Many people say after 30 days the gas looses a whole lot & shouldn't be run through 2 strokes, but i'v put gas in my toyota 4x4 on my duck club [ island ]& left it for 6 months & it fired right off.
Did you disconnect the linkage from the throttle body & push the throttle on the body as far as it would go?
Then reconnect the linkage & see how far it advances with the engine off.
90% of engine problems on 2 strokes is fuel related [ old or contaminated ] but if the 4 strokes are like autos, they should be able to digest it as long as there was some fuel additive put in it to prolong it's life.
You really should try a fresh 6 gallon tank to see if it helps.
Want_a_Whaler posted 07-10-2003 01:40 PM ET (US)     Profile for Want_a_Whaler  Send Email to Want_a_Whaler     
Just wanted to update on this post. I had the carbs rebuilt and it made all the difference in the world. I am running the 15" SS Honda prop and now she pops right up on plane and accelerates very nicely. Now the problem is that I think the 15" may be too small. When I get near WOT my Tach starts jumping from the high 5000s to 6800. I can't tell by the sound of the engine whether the prop is actually slipping and causing it or if its just the tachometer freaking out. When I ran it, it was just me and a small 3 gallon tank and the main tank only has about 8 gallons of the old crap fuel left which I plan to empty. I am going to fill the tank to add the weight back and take a couple people for a spin to see if the RPMs still shoot up. According to Perry's earlier posts and some emails, this is probably the right prop but when I bought the boat they had a 17" on it. I guess at this point it will be a question of hole shot vs top end. Any thoughts?
Perry posted 07-10-2003 03:21 PM ET (US)     Profile for Perry  Send Email to Perry     
I'm glad that the carb rebuild helped. What is the top speed now? I run the Honda 16 pitch stainless performance prop on my boat and I get 6000 rpm at wot although it isn't quite as quick out of the hole as the 13.75 X 15 pitch Solas prop I also use. Maybe you should try the Honda 16 pitch ss prop because 6800 rpm is way to high revs.

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